1. Field of the Invention
The present invention relates to a force feedback and sensing system for the hand for providing an interface to an interactive system.
2. Description of the Related Art
Force feedback human interface devices are used to track a user's manual gestures and provide means of presenting physical sensations back to the user. A force feedback device typically includes sensors for tracking a user's motions and actuators for producing physical forces.
Conventional systems have used the human hand to control both non-dextrous and dextrous slave devices. U.S. Pat. No. 5,004,391 ('391) issued to one of the inventors of the present disclosure describes a compact, hand-held unit that fits within the space defined by the user's palm and fingers and functions as a position controller for a robot having a slave hand. A finger position sensor including a linear, variable differential transformer provides an output signal that is proportional to the distance between the user's fingers. A force feedback system, including a pneumatic micro-actuator, senses the forces exerted by the end effectors of the robot hand and causes a corresponding force to be exerted on the user's fingers. The foregoing invention was intended primarily for use between the thumb and middle finger of the operator's hand. As such, it limited the ability to provide force feedback between any other fingers of the hand and also required the usage of a special sensor system using a linear differential transformer between the two manipulating digits.
U.S. Pat. No. 5,354,162 issued to one of the inventors of the present disclosure describes an improvement over the '391 patent in which a sensor glove is combined with a force feedback system. An actuator system provides force feedback to a master support. A first, second, third and fourth digit supports are connectable by a finger mount to the thumb, index, middle, and ring digits, respectively. First, second, third and fourth actuators comprising pneumatic cylinders extend between the first, second, third and fourth finger mounts and an “L” shaped palm support mountable on the palm of the glove. Sensors are mounted to the pneumatic cylinders to provide electrical signals on the positioning of the fingers. The signals are forwarded by a stand alone electronic interface to a host computer. The host computer computes the positioning of the finger and provides feedback to the first, second, third and fourth actuators.
U.S. Pat. No. 6,028,593 describes a method and apparatus for providing force feedback to a user operating a human/computer interface device and interacting with a computer generated simulation. In one aspect, a computer-implemented method simulates the interaction of simulated objects displayed to a user who controls one of the simulated objects by manipulating a physical object of an interface device. The position of the simulated object, as provided within the simulation and as displayed, is mapped directly to the physical position of the user object. The apparatus provides force feedback to the user which imparts a physical sensation corresponding to the interaction of the simulated objects.
Sensorial modalities have been used to increase simulation realism during virtual object manipulation. Haptic gloves have been used as haptic interfaces. Examples of haptic gloves have been described as the “Rutgers Master” in Gomez, et al., “Integration of the Rutgers Master II in a Virtual Reality Simulation,” IEEE Virtual Reality Annual International Symposium, pp. 198–202, (1995), as the “LRP Glove” in M. Bouzit, “Design, Implementation and Testing of a Data Glove with Force Feedback for Virtual and Real Objects Telemanipulation,” Ph.D. Thesis, Paris, France, (1996), as the “CyberGrasp” in Turner, et al., “Preliminary Tests of an Arm-Grounded Haptic Feedback Device in Telemanipulation,” Winter Annual Meeting of ASME'98, TX, DSC-Vol. 64, pp. 145–149, Nov. 15–21, Dallas, (1998). Force feedback bandwidth for these devices is in the range of 10–50 Hz. The gloves have one or more force degrees of freedom (DOF) per finger with forces grounded in the palm or on the back of the hand. A virtual hand maps the user's hand to a virtual environment.
It is desirable to provide an improved hand force feedback and sensing system that is lightweight and yet powerful. It is also desirable to have a system that adapts to various hand sizes.